Simulidce ■■ 



1 66 AN ACCOUNT OF BFITISH FLIES. 



insects, and even when stationary, continually move their front legs 

 about, using them as feelers. 



This family is distinguished by the following characters : (i.) the 

 scutum of the mesothorax undivided ; (ii.) the tibise and metatarsi 

 broad, short and compact ; (iii.) ocelli absent, which easily alone are 

 sufificient to distinguish it from the Bibionidse. The family has been 

 described under the following names : 



I Tipidarice latipeiinis, Mg. 

 I Svnultdes, Zett. 

 Si'imlites, Newn. 

 Sinm/ince, Rond. 



The larva are aquatic and cylindrical, and live in the stems of 

 water plants. The head is armed with the usual mouth parts and 

 two antenna. The larva of S. sericeiim is slender in the middle, and 

 lives in the stems of Phellandriu?n and of Stum, and has several 

 curious appendages as described by Fries. On the head, besides the 

 antennae, are two peculiar hairy, flabelliform appendages, and under- 

 neath the thorax is figured a tubular process ; whilst on the anal 

 segment are several curved appendages. 



The. ptipcE are as remarkable as the larvae, they have on each side 

 of the front of the sides of the thorax, eight very long filiform 

 appendages, arising in pairs analogous to the appendages of the 

 pupa of Chironomus ; the posterior part of the body is enclosed in 

 a semi-oval membranous cocoon attached to the plants and open in 

 front. According to Audouin, it appears that the cocoon is formed 

 entire by the larva, and afterwards eaten away as far as the thickened 

 arch previously formed ; the object of this contrivance being evidently 

 to let the water act upon the long filaments of the pupa, which no 

 doubt are air-tubes. The imago is hatched beneath the water, 

 the tomentum serving to repel it. All the larvae seem to be 

 aquatic and to live in the stems of plants, where pupation takes 

 place. The females are all very objectionable creatures, and follow 

 the traveller long distances, frequently attacking him and crawling 

 down the neck, and thus getting under the clothes. The males are 

 harmless, and often fly in circles in the air ; these " dances " are very 

 curious to watch ; they may often be seen in woods in England ; 

 when at rest^ the males may be found on the leaves of trees and on 

 flowers. Beech woods seem to be one of their favourite resorts, in 

 June and July. According to Zetterstedt,* the common English 

 species, S. repta?is, is found even in the snow on the mountain sides 

 and summits in Lapponica. 



The geological range extends back to the Purbeck period, where 

 * Ins. Lapp., pp. So2, 144. 



